We are sorry to hear this unfortunate situation happened to you Zeks. We have already contacted the factory to double check the product.

We have also made careful study of this situation and come to a general conclusion: there may be invisible defect caused during the shipment or probably some tension point in the glass that turned into a crack over time from the first use.

Of course, even though a product has passed serious certification there maybe also have problem during manufacturing, shipping and using. As we all know that the glass is a kind of fragile material and the same as Sandra said that “It’s a production thing, and it could happen to any double-walled cups on the market.” It is important that once such issue happened we need to check and find problem and solve it.

No matter what caused the problem we pay great attention and will update here once we get further news from factory. And we will also do more test on the cup.

We tested and recorded the performance of our glass teapots and double-wall tea cups under instantaneous temperature change. We tested tea cups and teapots at -8℃ that were frozen for 48 hours in the fridge and 2 tea cups at room temperature, with boiling water at 100℃. The result shows that our glass tea wares are safe under instantaneous temperature change.